Field of the Invention
The present invention relates to a method and to tooling for assembling a guide vane stage, in particular for a low pressure compressor of a turbine engine.
Description of the Related Art
In a turbine engine compressor, a guide vane stage comprises two axial shrouds extending one inside the other and interconnected by substantially radial airfoils that are fastened via their radial ends to the shrouds.
The outer shroud of the guide vane stage has radial orifices in which the radially outer ends of the airfoils are engaged and fastened, generally by welding. The inner shroud includes radial orifices in which the radially inner ends of the airfoils are engaged with clearance gaps, these gaps presenting a width lying in the range 2 millimeters (mm) to 3 mm, approximately.
In the prior art, the inner ends of the airfoils are secured to the inner shroud by means of a polymerizable sealing resin that is applied to the inner surface of the inner shroud and that, after hardening, serves to fasten the airfoils to the inner shroud. The resin forms an annular lock inside the inner shroud with the radially inner ends of the airfoils being embedded therein and with its internal periphery defining an abradable track for co-operating with annular wipers of a rotor in order to form a labyrinth type seal.
Prior to applying the resin to the inner shroud, the resin is injected into the above-mentioned gaps between the airfoils and the edges of the orifices in the inner shroud, all around each of the airfoils. This serves to fill in the gaps in advance so as to avoid any resin subsequently passing through the gaps while it is being applied to the inner shroud (so as to avoid wasting resin and so as to limit the time required for cleaning the guide vane stage in order to eliminate any runs of resin). Resin is injected into the gaps by means of a syringe that is filled by an operator, with this injection step being lengthy and expensive (taking about 8 hours for a single guide vane stage), difficult, messy, and difficult to make reproducible. In order to limit runs of resin while it is being applied, it is possible to store the resin in a refrigerator prior to applying it so as to increase its viscosity. Nevertheless, although that makes it easier to put the resin into place, it makes managing batches of resin more complex.